The overall objectives of this project are the following. We intend to obtain electrophoretically pure pea seedling diamine oxidase (DAO) for comparative studies with those previously performed on the hog kidney DAO. Resolution of the prosthetic groups from these enzymes and reconstitution of the enzymes will be performed to determine the nature of their binding and their functions. We will continue paramagnetic ion induced nuclear relaxation measurements to map the active sites of these enzymes with respect to the Cu(II) ion to further elucidate the mechanism of action of DAO and that of its inhibition at high substrate levels. Finally, we hope to initiate studies of the possible effects of DAO activity on DNA-bound amines which are DAO substrates to determine whether or not DAO can affect DNA transcription and replication.